Description

Product Description

The imaging principle of a fluorescence microscope is based on the physical phenomenon that certain molecules absorb light of a specific wavelength (excitation light) and then emit light of another wavelength (emission light). This technique is widely used in biological research to study the absorption, transport, distribution, and localization of substances within cells.

Fluorescence microscopes are mainly used to examine organic and inorganic samples. They typically use fluorescence and phosphorescence to reveal the structure, organization, and spatial distribution of samples. They are especially suitable for complex specimens that cannot be analyzed under conventional transmitted-light microscopes.

Two Types of Fluorescence Microscopes

  • Transmitted-type fluorescence microscope: Similar to a standard optical microscope, the light source travels from the base through a condenser to excite fluorescence in the sample. The light then passes through the objective and finally reaches the eyepiece.
  • Epi-illuminated fluorescence microscope: The most common type, used in most fluorescence microscopes. The light source is directed through the objectiveonto the sample. After excitation, the emitted fluorescence returns back through the objective and reaches the eyepiece.

Technical Description

Experiment Summary

Fluorescence microscopes are primarily used to study organic and inorganic samples. They use fluorescence and phosphorescence to analyze the structure, organization, and spatial distribution of specimens, making them ideal for complex samples not observable with traditional transmitted-light microscopy.

Two Types of Fluorescence Microscopes

  • Transmitted-type: Similar to a standard optical microscope. Light travels from the base, through the condenser, excites the sample, passes through the objective, and reaches the eyepiece.
  • Epi-illuminated type: The most common configuration. Light is directed through the objective onto the sample. Fluorescence emitted from the sample travels back through the objective to the eyepiece.

Operating Procedure

  1. Excitation light irradiation: A high-intensity light source (such as xenon lamp, mercury lamp, or laser) generates excitation light of a specific wavelength. Optical filters guide this light onto the specimen.
  2. Fluorescence emission from the sample: Fluorescent molecules (fluorescent dyes or fluorescent proteins) in the sample absorb excitation energy and enter an excited state. They then return to the ground state by emitting light at a longer wavelength—this emitted light is fluorescence.
  3. Filtering and imaging: The fluorescence passes through an emission filter that blocks residual excitation light, allowing only the desired fluorescence wavelength to pass. The microscope’s detection system (eyepiece, camera, etc.) captures this emission to form a clear sample image.

Experiment Objectives

Based on the fluorescence phenomenon—where certain substances absorb light at a specific wavelength and emit light at a different wavelength—this technique is widely used in biological research for studying intracellular transport, distribution, and localization of chemical substances.

  1. Specific molecular labeling and observation: Fluorescent labeling allows visualization of specific molecules or structures (proteins, DNA, RNA). Fluorescent probes enable direct observation of their distribution and dynamics.
  2. High-contrast imaging: Fluorescence microscopy provides an extremely high signal-to-noise ratio. Unlabeled regions of the sample typically do not emit light, reducing background interference and greatly improving visibility and contrast.
  3. Live-cell dynamic imaging: Supports real-time observation of dynamic processes in living cells or tissues, such as cell division, molecular transport, and signal transduction.
  4. Multi-labeling and multi-color imaging: Multiple fluorescent dyes with distinct emission wavelengths enable simultaneous labeling and observation of different biological targets, revealing their relative positions and interactions.
  5. Three-dimensional imaging: Combined with techniques such as confocal microscopy, fluorescence microscopy can scan fluorescence signals at different focal planes to reconstruct 3D images of the sample.

 

Assembly

 

Application Examples